Goldman-Hodgkin-Katz Equation (E2)

Question 1

What does the GHK equation allow us to do?

KEYWORDS/TERMS: Estimation, millivolt value, RMP, permeable, monovalent ions

Answer 1

Calculate an estimation of the millivolt value of the resting membrane potential (RMP) when the membrane is permeable to all 3 common monovalent ions

Question 2

What is the formula for the GHK equation?

Answer 2

V_m = (RT/F) * log((P_K[K⁺]_o + P_Na[Na⁺]_o +P_Cl[Cl^-]_i) / (P_K[K⁺]_i + P_Na[Na⁺]_i +P_Cl[Cl^-]_o))

Question 3

What does variable V_m stand for?

Answer 3

Resting membrane potential (RMP)

Question 4

What does variable R stand for?

Answer 4

Ideal gas constant (0.08206 mol/K)

Question 5

What does variable T stand for?

Answer 5

Absolute temperature in Kelvin (Celsius + 273.15)

Question 6

What does variable F stand for?

Answer 6

Faraday’s constant (96,485 coulombs/mol)

Question 7

What does variable P_ion[ion]_o stand for?

Answer 7

Cell membrane ionic permeability from the outside

Question 8

What does variable P_ion[ion]_i stand for?

Answer 8

Cell membrane ionic permeability from the inside

Question 9

Come up with a mnemonic for the order of the ions (i.e., K⁺, Na⁺, Cl^-) from the GHK equation.

Answer 9

Kill Nadine’s Clown

Question 10

List the pattern of “insides” and “outsides” in the GHK equation.

Answer 10

Out Out In
In In Out